Machines of this kind are known, which comprise a framing adapted to contain at least one bale, and a carriage, guided to slide both vertically and horizontally in the framing and carrying the carding cloth, the latter being driven in rotation by a motor mounted on the carriage in question. In the vicinity of the outlet end of the carding cloth there is mounted, on the carriage itself and parallel to the actuating and supporting rollers for the carding cloth, a loosening cylinder which is adapted to transfer the fibres withdrawn by the carding cloth to a conveyor belt which is arranged also in the framing. The conveyor belt transfers the fibres to the preparatory stages for spinning.
The engagement of the bottom lap of the carding cloth with the upper lap of the bale causes a fibre loosening which is only seemingly restricted by the active surface of the card cloth.
However, on account of the fact that the bales are formed by pressed fibres of irregular quality and having an uneven density, the detachment of the fibres from the bales takes place in lumps and tangles of different sizes so that fibres are also withdrawn which are outside said active surface of the carding cloth.
Inasmuch as the fibre bales are compressed lapwise, there is also the danger that the carding cloth may loosen parts of laps of the same bale and this, of course, would prejudice the regular operation of the machines which follow or cause jammings. In other cases, conversely, due to the presence of said lumps, entanglements and so forth, the percentage of one of the components of the fibre mix obtained could be altered, the result being a worsening of the quality of the end product.